BIOSTASTICS SHARED RESOURCE (BSR): PROJECT SUMMARY The Biostatistics Shared Resource (BSR) provides Siteman Cancer Center (SCC) research programs with access to cancer-focused statistical expertise, including design of early phase clinical trials, longitudinal data analysis, biomarker discovery, statistical methods for high dimensional genomic data, and risk prediction/risk stratification development and validation. BSR statisticians are integrally involved in all seven SCC research programs with 142 SCC member users in 2018. They function as scientific collaborators in clinical trial and interventional protocols; advising on, and participating in, study design, creating and managing research databases, overseeing statistically relevant issues in trial/project implementation, conducting interim and final data analyses, presenting research data/methods, and interpreting results. BSR contributes to research rigor and reproducibility through active involvement in scientific review and oversight activities. In collaboration with the SCC Clinical Trials Core (CTC), BSR statisticians develop study-specific data collection forms and conduct data monitoring. BSR faculty serve on the SCC Protocol Review and Monitoring Committee (PRMC) and the SCC Quality Assurance and Safety Monitoring Committee (QASMC), providing statistical reviews of all new protocols and assuring proper statistical conduct of all active protocols. BSR faculty collaborate on numerous National Cancer Institute-funded projects and have contributed significantly to the high quality science and research productivity of SCC programs. In the current project period alone, BSR faculty have authored over 250 peer-reviewed statistical methodology and cancer-related publications with 44 in high-impact journals (Thomson Reuters impact factor of 10 or greater). This contribution illustrates the wide range of research and methodologic expertise available to SCC members through the BSR. In the next project period, BSR will continue to grow with increased capacity in statistical support for electronic health record-based comparative effectiveness research, cancer immunotherapeutic trials, biomarker studies, and precision medicine initiatives.